Events Calendar

EVENTS IN August 2013

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Thursday, August 29, 2013

3:00 PM - 4:00 PM

ANSER Special Seminar - Jenny Nelson of the Imperial College London

Dr. Jenny Nelson of the Imperial College London will visit Northwestern to deliver a special ANSER seminar, titled "Charge Pair Generation and Recombination in Photovoltaic Heterojunctions."

 

Abstract:

The nature of the donor: acceptor interface in a photovoltaic heterojunction solar cell controls the efficiency of photo‐induced charge generation and the mechanism of charge recombination. We have studied the processes of charge generation and recombination in a series of organic polymer:fullerene heterojunctions and hybrid organic:inorganic heterojunctions using device measurements, theoretical modelling, electroluminescence spectroscopy, and time resolved optical spectroscopies. We find that the efficiency of charge pair generation can be correlated to both the size of the free energy offset driving charge transfer and to the extent of ordered domains in either material which enable the electronic states to delocalise. Charge generation efficiency can thus be controlled via processing steps that modulate the degree of order in the microstructure. Preliminary measurements indicate that the cost of charge separation in hybrid heterojunctions may be less than in all organic systems. Charge recombination is influenced by the size and degree of order of domains but also, importantly, by the ease of charge transport which depends on the self‐organising tendency of the materials as well as the intrinsic mobility. Using results from a range of material systems, we discuss the influence of interface, microstructure and material type on device performance.

 

Bio:
Jenny Nelson is a Professor of Physics at Imperial College London, where she has researched novel varieties of material for use in solar cells since 1989. Her current research is focussed on understanding the properties of molecular semiconductor materials and their application to organic solar cells. This work combines fundamental electrical, spectroscopic and structural studies of molecular electronic materials with numerical modelling and device studies, with the aim of optimising the performance of solar cells based on molecular and hybrid materials. Since 2010 she has been working together with the Grantham Institute for Climate Change to explore the mitigation potential of photovoltaic, and other renewable, technologies. She has published over 200 articles in peer reviewed journals, several book chapters and a book on the physics of solar cells. She was awarded the 2009 Institute of Physics Joule Prize and medal and the 2012 Royal Society Armourers and Brasiers Company Prize for her research.


Research areas:
‐ Multi‐scale modelling of molecular electronic materials
‐ Device physics of organic and hybrid solar cells
‐ Electronic, spectoscopic and structural characterisation of molecular electronic materials
‐ Mitigation potential of solar photovoltaic technology

 

Please contact Ria Hirsch, r-hirsch@northwestern.edu with all questions.

Contact Info: Ria Hirsch

Location: Pancoe-NSUHS Life Sciences Pavilion 2200 Campus Drive Pancoe Auditorium Evanston, IL 60208

ANSER Special Seminar - Jenny Nelson of the Imperial College London

Dr. Jenny Nelson of the Imperial College London will visit Northwestern to deliver a special ANSER seminar, titled "Charge Pair Generation and Recombination in Photovoltaic Heterojunctions."

 

Abstract:

The nature of the donor: acceptor interface in a photovoltaic heterojunction solar cell controls the efficiency of photo‐induced charge generation and the mechanism of charge recombination. We have studied the processes of charge generation and recombination in a series of organic polymer:fullerene heterojunctions and hybrid organic:inorganic heterojunctions using device measurements, theoretical modelling, electroluminescence spectroscopy, and time resolved optical spectroscopies. We find that the efficiency of charge pair generation can be correlated to both the size of the free energy offset driving charge transfer and to the extent of ordered domains in either material which enable the electronic states to delocalise. Charge generation efficiency can thus be controlled via processing steps that modulate the degree of order in the microstructure. Preliminary measurements indicate that the cost of charge separation in hybrid heterojunctions may be less than in all organic systems. Charge recombination is influenced by the size and degree of order of domains but also, importantly, by the ease of charge transport which depends on the self‐organising tendency of the materials as well as the intrinsic mobility. Using results from a range of material systems, we discuss the influence of interface, microstructure and material type on device performance.

 

Bio:
Jenny Nelson is a Professor of Physics at Imperial College London, where she has researched novel varieties of material for use in solar cells since 1989. Her current research is focussed on understanding the properties of molecular semiconductor materials and their application to organic solar cells. This work combines fundamental electrical, spectroscopic and structural studies of molecular electronic materials with numerical modelling and device studies, with the aim of optimising the performance of solar cells based on molecular and hybrid materials. Since 2010 she has been working together with the Grantham Institute for Climate Change to explore the mitigation potential of photovoltaic, and other renewable, technologies. She has published over 200 articles in peer reviewed journals, several book chapters and a book on the physics of solar cells. She was awarded the 2009 Institute of Physics Joule Prize and medal and the 2012 Royal Society Armourers and Brasiers Company Prize for her research.


Research areas:
‐ Multi‐scale modelling of molecular electronic materials
‐ Device physics of organic and hybrid solar cells
‐ Electronic, spectoscopic and structural characterisation of molecular electronic materials
‐ Mitigation potential of solar photovoltaic technology

 

Please contact Ria Hirsch, r-hirsch@northwestern.edu with all questions.

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